1867.] 



with the PyrO' and Tetra-phosphoric Amides, 



515 



pound, like tlie pyro-diamic acid, may be prepared from tbe higber 

 amidated oxycbloride, and the process is capable of the same expla- 

 nation. The three stages, probably simultaneous, are as follows : — 



2P(NH,),C10+ |}o=2HCl+J(Jg^g}OorP,(NH,),0„ 

 2P, (NHJ, O3+ H } o = 2N H,+^= } O, 



P,(NH,)3 03 r+^Hl °-^^^' + P,(NHJ,(HO) O3/ 

 which is (N HJ^ Og, tetrapTiosplio-tetramic acid. 



The tetrapliospJioric acid, of which this is the fourth amide, must be 

 P^ Hg 0^3, a substance already known, at least in its salts, for it is 

 Pleitmann and Henneberg's phosphoric acid. 



On the view given aboye the rational formulae of the four phosphoric 

 acids may be thus expressed : — 



Ortho-phosphoric acid P (H 0)3 O. 



Meta-phosphoric acid pj'^^jo. 



Pyro-phosphoric acid ^ ^ j'^ ^ | O. 



Tetra-phosphoric acid P (H 0) 



P(HO),0|J. 



P(HO),0|q 

 J 



o. 



P(HO) 



It is more difficult to assign satisfactory rational formulae to the two 

 compounds containing P^Ng.... The fact that the atoms of nitrogen 

 are uneven in number destroys the symmetry, and seems to point to 

 their being products of decomposition of substances containing P^Ng.... 

 That they both belong to the tetraphosphoric series is evidenced by 

 their giving rise easily to tetraphospho-tetramic acid. 



The reactions of the liquid P^ H^^ O^^ indicate that it is an acid 

 ammonium salt, or is readily transformable into such. Hence I have 

 called it terammoniated tetrapJiospTio-diamic acid, and its formula will be 

 P(NH,) (NH,0)0|^. 



I (N H,) (S O) O 1 ^ - ^I^X HJ, H 0,, 



P (NH,0)OJ^J 

 The formation of a tetra.phospho-tetramate from a salt of this structure 

 would be analogous to the ready passage of pyrophosphate of ammonium 

 into a pyrophosphamate. 



The acid P^ 'N- Hg O^, to which has been given the provisional name 

 tetrajjJiospJio-pentazotic acid, is perhaps derived from the decomposition 

 of tetraphospho-hexamide, P^ (N Jio)^ O7, which is the complete amide 

 of tetraphosphoric acid, and is a very likely substance to be formed by 



